Using bound variables in Tkinter events

[Derek Fountain]

>> I'm coming to Tkinter from Tcl/Tk. In Tcl I can get a variable in an
>> event using the %<X> substitution mechanism. For example, I can set up a
>> command like:
>>
>>  entry .e -validate 1 -vcmd "checkkey %d"
>>
>> knowing that the '%d' will be replaced by something useful - whether the
>> entry widget has recieved an insert or deletion in this case. The
>> checkkey procedure will recieve "insert", "delete" or whatever as its
>> first parameter.
>>
>> What is the Tkinter way of getting that %d value?
> 
> It's in the event object that's passed as the (only) parameter
> to your event handler. Everything you ever wanted to know
> about the event is an attribute.

The validate command doesn't get an event.

> There are a number of very good references to Tkinter on
> the first page of the Python Library Reference section on
> Tkinter. (That's section 16 in the Python 2.3 reference)

Indeed, but I couldn't find anything which answered this question.